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authorRoland McGrath <roland@gnu.org>1995-05-02 06:35:55 +0000
committerRoland McGrath <roland@gnu.org>1995-05-02 06:35:55 +0000
commitd66e34cd423425c348bcc83df127dd19711b0b9a (patch)
tree97058e776d3b4fe06ef54bc4951596991652183f /elf/dl-lookup.c
parent08162fa888913a5153d2fcdc4e1a816b57b1fe56 (diff)
downloadglibc-d66e34cd423425c348bcc83df127dd19711b0b9a.tar.gz
* sysdeps/mach/i386/sysdep.h (SNARF_ARGS, CALL_WITH_SP): Rewritten.
* sysdeps/i386/dl-machine.h: New file. * sysdeps/stub/dl-machine.h: New file. * sysdeps/i386/dl-runtime.c: New file. * sysdeps/stub/dl-runtime.c: New file. * sysdeps/i386/elf/start.S: New file. * sysdeps/generic/dl-sysdep.c: New file. * sysdeps/mach/hurd/dl-sysdep.c: New file.
Diffstat (limited to 'elf/dl-lookup.c')
-rw-r--r--elf/dl-lookup.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
new file mode 100644
index 0000000000..b4600b1970
--- /dev/null
+++ b/elf/dl-lookup.c
@@ -0,0 +1,129 @@
+/* Look up a symbol in the loaded objects.
+Copyright (C) 1995 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+#include <stddef.h>
+#include <libelf.h>
+#include <link.h>
+
+/* Search loaded objects' symbol tables for a definition of
+ the symbol UNDEF_NAME. Don't use a PLT defn in UNDEF_MAP, since
+ that is the object making the reference. */
+
+Elf32_Addr
+_dl_lookup_symbol (const char *undef_name, const Elf32_Sym **ref,
+ struct link_map *symbol_scope)
+{
+ unsigned long int hash = elf_hash (undef_name);
+ struct link_map *map;
+ struct
+ {
+ Elf32_Addr a;
+ const Elf32_Sym *s;
+ } weak_value = { 0, NULL };
+
+ /* Search the relevant loaded objects for a definition. */
+ for (map = symbol_scope; map; map = map->l_next)
+ {
+ const Elf32_Sym *symtab;
+ const char *strtab;
+ Elf32_Word symidx;
+
+ symtab = ((void *) map->l_addr + map->l_info[DT_SYMTAB]->d_un.d_ptr);
+ strtab = ((void *) map->l_addr + map->l_info[DT_STRTAB]->d_un.d_ptr);
+
+ /* Search the appropriate hash bucket in this object's symbol table
+ for a definition for the same symbol name. */
+ for (symidx = map->l_buckets[hash % map->l_nbuckets];
+ symidx != STN_UNDEF;
+ symidx = map->l_chain[symidx])
+ {
+ const Elf32_Sym *sym = &symtab[symidx];
+
+ if (sym->st_value == 0)
+ continue;
+
+ switch (ELF32_ST_TYPE (sym->st_info))
+ {
+ case STT_NOTYPE:
+ case STT_FUNC:
+ case STT_OBJECT:
+ break;
+ default:
+ /* Not a code/data definition. */
+ continue;
+ }
+
+ if (sym == *ref)
+ /* This is the same symbol we are looking for the value for.
+ If it is a PLT entry, it will have a value of its own;
+ but that is not what we are looking for. */
+ continue;
+
+ if (strcmp (strtab + sym->st_name, undef_name))
+ /* Not the symbol we are looking for. */
+ continue;
+
+ switch (ELF32_ST_BIND (sym->st_info))
+ {
+ case STB_GLOBAL:
+ /* Global definition. Just what we need. */
+ *ref = sym;
+ return map->l_addr;
+ case STB_WEAK:
+ /* Weak definition. Use this value if we don't find another. */
+ if (weak_value.a == 0)
+ {
+ weak_value.s = sym;
+ weak_value.a = map->l_addr;
+ }
+ break;
+ default:
+ /* Local symbols are ignored. */
+ break;
+ }
+ }
+ }
+
+ if (weak_value.s == NULL)
+ {
+ const char msg[] = "undefined symbol: ";
+ char buf[sizeof msg + strlen (undef_name)];
+ memcpy (buf, msg, sizeof msg - 1);
+ memcpy (&buf[sizeof msg - 1], undef_name, sizeof buf - sizeof msg);
+ _dl_signal_error (0, msg);
+ }
+
+ *ref = weak_value.s;
+ return weak_value.a;
+}
+
+
+/* Cache the location of MAP's hash table. */
+
+void
+_dl_setup_hash (struct link_map *map)
+{
+ Elf32_Word *hash = (void *) map->l_addr + map->l_info[DT_HASH]->d_un.d_ptr;
+ Elf32_Word nchain;
+ map->l_nbuckets = *hash++;
+ nchain = *hash++;
+ map->l_buckets = hash;
+ hash += map->l_nbuckets;
+ map->l_chain = hash;
+}